1) Field of the Invention
The present invention relates to technology for distributing load of a host apparatus in a POS (Point of Sale) system.
2) Description of the Related Art
Japanese Patent Application Laid-Open Nos. 5-054211, 8-329350, and 11-120240 disclose the conventional POS systems.
One approach employed in the POS systems is to optically read a bar code attached to an article and obtain information about the article from a host computer based on the read bar code. The bar code is read with a bar code reader or a bar code scanner. The information, which contains characters, about the article includes name of the article, price of the article, information about expiry dates, if any, of the article.
FIG. 7 is a block diagram of a conventional POS system. Bar code readers 101 to 10n are placed at various locations in the shop or the department store. These bar code readers 101 to 10n have an arrangement to optically read a bar code attached to an article. The read bar code information is transmitted to the host apparatus 20.
A bar code represents information in the form of black and white bars. The bar code readers have a laser diode to emit laser and scan the bar code with the laser, a light receiver to receive the light reflected from the bar code, signal converter to convert the received light to electric signal, and a means to convert the electric signal into the bar code information and send the bar code information to the host apparatus 20.
A storage containing a PLU file 30 is attached to the host apparatus 20. This PLU file 30 contains information about all the articles (hereinafter, “article information”) in that particular shop or the department store. The article information includes name of the article, price of the article etc. The article information for an article is stored in correspondence with the bar code information of that article. Thus, when the host apparatus 20 receives a bar code information from any of the bar code reader 101 to 10n, it retrieves the article information, and sends the article information to the bar code reader from where the bar code information was received.
The storage containing a PLU file 30, for example, stores term information, which represents a period until which the article can be sold or eaten (hereinafter, “the term of the article has expired”), in correspondence with the bar code information of that article. The host apparatus 20 has a timer which keeps an account of time, (for example, date, hour, and minute) when the bar code information is received (hereinafter, “current time”). When the host apparatus 20 receives a bar code information from a bar code reader, it retrieves the term information corresponding to that article and checks whether the current time is within the period represented in the term information. If the current time is later than the period represented in the term information, then the host computer 20 send a signal to the bar code reader from where the bar code information was received to display a warning on the display of that bar code reader.
When an operator of the bar code reader sees such a warning on the display, it means that the term of the article has expired, and he/she performs a processing to cancel the purchase of the article.
The bar code reader 10n, for example, is a handy reader and can be used for the inventory of articles. In this case, the operator scans the bar code of an article to be displayed on shelves. As a result, the bar code information of that article is transferred from the bar code reader 10n to the host apparatus 20. The host apparatus 20 compares the term information with the current time, and checks whether the term of the article has expired. If the term of the article has expired, the host apparatus 20 transmits a signal to the bar code reader 10n to display on the display of the bar code reader 10n that the term of the article has expired. When such warning is displayed on the display of the bar code reader 10n, the operator does not place the article on the shelf.
The conventional POS systems have a problem that, since only the host apparatus performs the retrieval of the article information and the term information and checking of whether the term of the article has expired, the host apparatus is always overload with work. In case of large-scale shops, there are over 100 bar code readers, and there is a huge load on the host apparatus 20. A high-end machine may be used as the host apparatus 20 to solve the problem of the overload, but that results in cost increase.